In a radio communication system, each of radio base stations allocates communication channels to a radio terminal visiting a cell provided by the radio base station. By using the allocated communication channels, the radio terminal connects with the radio base station which provides the visited cell, and communicates with the radio base station.
In the aforementioned communication, in a case where transmission power set for an uplink communication channel by the mobile terminal is fixed, an increase in distance between the radio terminal and the radio base station due to the moving of the radio terminal might deteriorate a communication quality.
In order to restrain such deterioration of the communication quality, a remedy as to be described below is taken in some cases. For example, in a radio communication system employing LTE (Long Term Evolution) which is a standard worked out by the 3GPP (Third Generation Partnership Project), a radio base station measures the communication quality of an uplink communication channel allocated to a radio terminal. If the communication quality falls below a predetermined level, the radio base station requests the radio terminal to increase transmission power.
In addition, when the same frequency band is used in the aforementioned communication for a communication channel between the radio base station and the radio terminal and a communication channel between another radio base station and another radio terminal, one communication channel might interfere with the other communication channel.
In order to restrain such interference, the radio base station requests the other radio terminal allocated the communication channel causing the interference to reduce transmission power (for example, see Patent Literature 1).    Patent Literature 1: Japanese Patent Application Publication 2002-247626